Assessing the impact of Mandatory Access Control (MAC) integration on the Linux kernel performance is still an open problem. Regarding the specific paradigm of MAC in High Performance Computing, there are actually few works. Yet, guaranteeing security properties on a shared cluster is both a necessity and a challenge. This is a necessity because it is mandatory to ensure the confidentiality and integrity of data computed by the users, and a challenge because a cluster is a costly resource built with performance in mind. This paper deals with the need to integrate MAC in Linux-based operating systems for HPC clusters in an efficient way.